Beneficial Insects

(J.P. Michaud) My name is J.P. Michaud, and I’m the entomologist here at the Agricultural Research Center at Hays. Here on our Wheat Day — Wheat Field Day — and as an entomologist, I look at this wheat, and I see a lot of beneficial insects right now. We’ve had fairly large numbers of aphids in the wheat this spring. They like the cool weather but these are not really an economic concern, and that my first point is people shouldn’t worry. It’s good to have some aphids in the wheat because what we’re really doing now is we’re breeding all the natural enemies, all the beneficial insects are increasing their numbers and that wheat is going to mature, and they’re all going to disperse. They’re going to go to those summer crops, and that’s where we are going to really need those insects this year if we have, as anticipated, an invasion of sugarcane aphid from the south on the sorghum. But as agronomists and as farmers, we tend to manage the farm field by field. Each field has its own history of soil fertility, crop rotation, et cetera. As an entomologist, I see the farm as an integrated unit because all the beneficial insects have to move between those crops. When we are thinking about retaining beneficial insects on the farm, we have to think about the fact that all those insects get up and move from the winter crops into the summer crops. We really want to be careful about spraying any unnecessary insecticide treatments in the wheat. We’ve had a lot of stripe rust with the wet weather and so the inclination for some people is, Well, I’m already putting on an application for fungus. Maybe I should just throw a bit of insecticide in there for good measure, and it won’t cost me very much. That’s not good reasoning because if it doesn’t cost you very much it’s probably because it’s a cheap material. If it’s a cheap material, it’s going to kill a lot of good insects along with the bad. Second of all, it’s not sound IPM management because you really want to have a reason to put the insecticide in there. There’s no way that the aphid populations at this stage of the crop are going to do much damage to the wheat. All of these natural enemies, which are increasing their numbers right now in the wheat, are going to be especially important for us this year when the green sorghum comes up because we are expecting a very high probability of infestation by sugarcane aphid. This aphid has over-wintered further north this year than previous years, about 50 miles north of Lubbock on Johnson grass. We’ve discovered it can over-winter on the roots of Johnson grass, and the area infested to the south is quite a much larger area than last year. Those bigger source populations are going to be coming at us. Where they go will depend largely on wind direction but the advice for the milos — if you’re planting milo — try and get it into the ground as early as you can, get as much growth on those plants before the aphids arrive, and prepare to budget for a possible insecticide application. We have emergency use registration for two very effective materials, Transform and Sivanto. While they are not cheap, but they are very effective against the aphids and they will spare beneficial insects. They are quite soft on beneficials. I won’t say they’re harmless but they’re much, much superior materials in terms of selectivity compared to what we’ve had to use against aphids in the past. Our hope is with these selective materials, that in fact, we’ll be able to accelerate the evolution of natural sustainable biological control in the crop.

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